Low-Power Wake-Up Radio (LP-WUR) breaks the trade-off between low power and availability currently realized by traditional radios. In order to conserve power, traditional radios are duty-cycled and periodically woken up to listen for data transmissions. However, this implementation is not without its drawbacks. If the sleep period is too long, data transmissions may be missed. If the sleep period is too short, then power is not efficiently saved. The ideal sleep period varies from case to case and is difficult to determine even during use-time. Ultimately, the sleep period length is set by an acceptable level of packet loss due to packets being missed during the sleep cycle.
With a LP-WUR, the main (i.e. traditional) radio can be powered off until a wake-up signal is detected by a low power wake up receiver. This wake up receiver is a separate unit to the device in addition to the main radio whose task is to wake up the main radio (i.e. the main receiver) when there is a request for a communication from another component of a wireless network. Since the more power intensive main receiver is only activated during data transfer and does not have to constantly monitor the wireless communication channels, power is saved and data packet loss is minimalized when compared to the traditional duty-cycled implementations.